Neodymium-138

Properties and data of the isotope ¹³⁸Nd.

Content

General data

Name of the isotope:Neodymium-138; Nd-138Symbol:¹³⁸Nd or 13860NdMass number A:138 (= number of nucleons)Atomic number Z:60 (= number of protons)Neutrons N:78Isotopic mass:137.911950(12) u (atomic weight of Neodymium-138)Nuclide mass:137.8790377 u (calculated nuclear mass without electrons)Mass excess:-82.01805 MeVMass defect:1.233415368 u (per nucleus)Nuclear binding energy:1148.9190148 MeV (per nucleus)
8.32550011 MeV (average binding energy per nucleon)Separation energy:S_N = 10.505(16) MeV (first neutron)
S_P = 6.106(14) MeV (first proton)Half-life:5.04(9) hDecay constant λ:3.820255624779 × 10^-5 s^-1Specific activity α:1.679278649152 × 10⁺¹⁷ Bq g^-1
4538590.9436549 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Charge radius:4.9123(26) femtometer fmYear of discovery:1965

Radioactive Decay

Half-life T_½ = 5.04(9) h (hours) respectively 1.8144 × 10⁴ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	¹³⁸Pr	100 %	1.116(16) MeV

Parent Nuclides

Direct parent isotope is: ¹³⁸Pm.

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
^138mNd	3174.5(4) keV	370(5) ns	10+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 78) and isobaric (same nucleon number A = 138) with Neodymium-138. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 78	Isobar A = 138
43	¹²¹Tc
44	¹²²Ru
45	¹²³Rh
46	¹²⁴Pd
47	¹²⁵Ag
48	¹²⁶Cd
49	¹²⁷In
50	¹²⁸Sn	¹³⁸Sn
51	¹²⁹Sb	¹³⁸Sb
52	¹³⁰Te	¹³⁸Te
53	¹³¹I	¹³⁸I
54	¹³²Xe	¹³⁸Xe
55	¹³³Cs	¹³⁸Cs
56	¹³⁴Ba	¹³⁸Ba
57	¹³⁵La	¹³⁸La
58	¹³⁶Ce	¹³⁸Ce
59	¹³⁷Pr	¹³⁸Pr
60	¹³⁸Nd	¹³⁸Nd
61	¹³⁹Pm	¹³⁸Pm
62	¹⁴⁰Sm	¹³⁸Sm
63	¹⁴¹Eu	¹³⁸Eu
64	¹⁴²Gd	¹³⁸Gd
65	¹⁴³Tb	¹³⁸Tb
66	¹⁴⁴Dy	¹³⁸Dy
67	¹⁴⁵Ho
68	¹⁴⁶Er
69	¹⁴⁷Tm
70	¹⁴⁸Yb
71	¹⁴⁹Lu